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An endohedral fullerene is a carbon cluster encapsulating atoms such as Li inside the fullerene and is a material anticipated to be practically applied to electronics and medical cares.
To synthesize the endohedral fullerene, methods of laser evaporation, arc discharge, ion injection, and plasma irradiation have been used. Besides the endohedral fullerene, many impurities such as empty fullerenes and the atoms, which were not encapsulated inside, are included in a product synthesized by these methods. Thus, in order to produce the endohedral fullerenes with high purity, it is necessary to separate the endohedral fullerene from these impurities and purify the endohedral fullerene.